Bearers and joistsSizes and
grades for bearers and joists are shown in the left hand column of
Tables 3, 4 and 5. Sections of greater size omitted from the tables
may still be available upon enquiry with individual producers. This
includes sections wider than 100mm wide and F22 stress grades
(seasoned or unseasoned). Producer's names can be sourced in the
Producers Guide referenced at the end of this document.

Large
bearers may require 'heart-in' which means the tree pith and
surrounding juvenile wood are included in the centre part of the
bearer. AS2082 (see note 2)‚ permits the heart in the central 1/9th
of the cross section, but only on sections 175 x 175mm or greater in
size. Caution is required with 'heart' material as it is subject to
heart shakes which are longitudinal fissures within the wood which
weaken large sections. One option to reduce the problem is to use
high density timbers with relatively low shrinkage rates, e.g. red
ironbark. These timbers are very strong and create less internal
shrinkage stresses, thus reducing heart shakes. Another option is to
reduce end-grain splitting and moisture loss by coating the ends
with a suitable sealer immediately after sawing. In addition, all
sections should be end-plated with multi-toothed plate connectors
covering at least 50% of the exposed end sections. Timber should be
specified with these features in place, prior to
delivery.